Joanna Yeates murder investigation Day 7: What police know

THE DISAPPEARANCEJoanna Yeates was last seen walking from the Ram pub in Bristol city centre to her home in Clifton on December 17 around 8pm. At 8:30pm she used her mobile phone to call a friend. CCTV shows her visiting three shops, with a stop at Tesco Express at 8:40pm as the last known sighting of her.

Police found her purse and timed shopping receipts in her flat, but do not yet know what happened inside. Three options being considered are that she let her killer - or killers - into the flat, that the killer was there, or that the killer broke in after her return.

THE PIZZA AND CIDER

Miss Yeates bought two bottles of cider from a Bargain Booze shop and a pizza from Tesco Express. One cider bottle was found half empty in the flat and the other was unopened. Police say the pizza is a "vital clue" and suspect the killer may have eaten the pizza and thrown the wrapper into a bin further from the search area. Officers still do not know if she ate the pizza, a full nine days after the post mortem examination. They also do not know who drank from one of the cider bottles.

WHERE JO WAS KILLED

A couple walking their dogs on Christmas Day at 9am found Miss Yeates's body slumped against a wall, which backs on to a deep quarry. Police are certain she was not killed there and are focusing forensic teams to her home. Police have not been able to confirm when she was killed and when her body was dumped in the country lane.

WHERE JO WAS FOUND

Miss Yeates was strangled, but the post mortem found no obvious signs of a sexual assault. She was fully clothed when found, but her coat was found in her flat. A DNA sample from another person was found on her body. Heavy snowfall which covered the body before Christmas made it difficult to determine an accurate timetable of her death.

It is not known if the DNA sample has provided the police with a full and unique DNA profile, or if it is so-called "low copy" DNA, which makes it much harder to identify a single individual.

THE MOTIVE

Police avoided declaring a prime motive for the murder, but admitted on Monday they were considering a sexual motive. Focus has been on people Miss Yeates knew, but other theories include her being followed to her flat by a random stalker or killed by a man whose advances were spurned, possibly during her drinking session after work the night she disappeared.

THE ARREST

On Monday, police revealed that the murderer might have had an accomplice. Boyfriend Greg Reardon is not a suspect because he was en route to Sheffield on the night Miss Yeates disappeared.Chris Jefferies, 65, was arrested on suspicion of murder on 23 December but released on bail two days later. He remains the only known suspect but insists he is innocent and is considering legal action.